1. Field of the Present Invention
The present invention relates to file verifying technology, and more especially to a method and a system for verifying making time of a file by computer.
2. Description of the Prior Art
Verifying making time of a file is an important part of criminal judicial appraisal, and is also a problem in the file verifying field. The technology of verifying making time of a file began in 1904. In the early stage such research focused on the writing by the fountain pen, and then expanded to the writing by the ball-point pen which occurred in 1937. Once upon a century, the scientists around the world put much efforts into verifying making time of a file, however, it is difficult to grasp the variation characteristics with time of the writing since the ink ingredients are complex, and the ink is prone to be influenced by the storage environment (e.g. temperature, humidity, light, oxygen, etc) and other interference factor (the category of paper, the power of writing, and the writing line is coarse or fine) resulting in the physical or chemical vitiation, such as oxidized, decomposed, cross linked, or volatilized. Verifying making time of a file is a big obsession for global scientists all the time.
Generally verifying making time of the file is such a way of analyzing variation with time of the ink ingredients with aid of chemical reaction between the chemical reagents and the ink, or an apparatus to determining making time of the file. At present, there are physical and chemical methods. Common methods include impressing, solvent extraction, sulfate diffusion measurement, TLC (Thin Layer Chromatography), HPLC (High Performance Liquid Chromatography), CE (Capillary Electrophoresis), GC-MS. (Gas chromatography-mass spectrometry), Fourier-infrared spectrometry, Raman spectrometry, microscopic spectrophotometry, FDMS (field desorption mass spectrometry), X-ray electronic energy spectrum, artificial ageing etc. Based on different principles, the aforesaid methods each of which has advantages and shortcomings can be combined in the case of without destroying the file.
The methods for verifying making time of the file often used in China include impressing, extraction solvent, measure of the diffusion of vitriol, TLC. The impressing method is a physical method, and the others are chemical methods by which analyze the making time of the file from the chemical reaction of ink ingredients. The impressing method analyzes the making time of the file by judging whether the writing on the file is transferable after impressed. Unfortunately, through this method, the making time of the file has a vague range, which significantly reduces the verifying accuracy. Those chemical methods often have to break the object file before verifying. In addition, due to the complex ink ingredients, the complexity of the chemical methods is greatly increased, and there are many uncontrollable factors, which brings certain limitation to the verifying condition and analysis result, and generates error to such result.
In conclusion, the physical method and the chemical methods for verifying making time of the file at present are very complicated in practice, and it is impossible to verify making time of the file very precisely. Additionally, it has high requirements for the object file and the sample file while the sample file offered by the applicant who requests to verify making time of the object file could not satisfy such specific requirements normally, whereby such verifying could not be achieved.